I always encourage my students to look up any words that confuse them as they read opinions. But this 2011 New York Times article cites a few scholars who don’t think it’s the most judicious practice to undertake from the bench. Check out this excerpt:

In May alone, the justices cited dictionaries in eight cases to determine what legislators had meant when they used words like ‘prevent,’ ‘delay’ and ‘report.’ Over the years, justices have looked up both perfectly ordinary words (‘now,’ ‘also,’ ‘any,’ ‘if’) and ones you might think they would know better than the next guy (‘attorney,’ ‘common law’).